The present invention relates to elastomeric gaskets and, more specifically, to a co-extruded gasket for providing a seal between a pair of tubular members that includes an elastomeric gasket portion and a support portion that presses the elastomeric portion into engagement with the tubular members.
It is well known to form a seal between two pipe sections, such as two corrugated pipe sections, where the end of one of the pipe sections has annular grooves and one of the pipe sections has an enlarged bell portion at one end. Some prior art elastomeric gaskets are placed around the end of the pipe section having annular grooves. The pipe section having annular grooves is inserted into an enlarged bell portion of a second pipe section. The elastomeric gasket contacts each of the pipe sections to form a seal between the pipe sections.
Some prior art gaskets are adapted to fit in the groove of a corrugated pipe or pipe connector. As one end of a pipe is pushed into the enlarged end or bell of another pipe section or pipe connector, the gasket is sometimes pulled from the groove and the pipe is not properly sealed. When the pipe is not properly sealed ground water may leak into the pipe or fluid may leak out of the pipe and contaminate the ground.
U.S. Pat. No. 4,702,502 attempted to solve the problem of the gasket being pulled from the annular grooves of a corrugated pipe when the corrugated pipe was inserted into a bell portion of a second corrugated pipe. The ""502 patent concerns a telescopic joint in low pressure corrugated plastic pipes. The joint includes a one piece elastomeric gasket that has a sealing portion adapted to be disposed in a groove in one of the pipes and an anchoring portion adapted to be disposed in an adjacent groove. As the pipes are telescoped together the anchoring portion is trapped in the groove and anchors the sealing portion in place as it is compressed.
U.S. Pat. No. 3,796,447 to de Putter concerns a corrugated pipe connector for connecting ends of two male pipes. A rubber sealing ring is maintained in a corrugation of the pipe connector by a maintaining ring. The maintaining ring avoids removal of the sealing ring from the corrugation of the pipe connector during insertion of the male pipe ends into the corrugated pipe connector.
U.S. Pat. No. 4,834,398 to Guzowski et al. concerns a pipe sealing gasket having a first portion formed out of a hard, relatively high durometer material and a second portion formed of a relatively lower durometer, more flexible material. The harder first portion of the gasket is contacted first as the pipes are assembled, causing the gasket to maintain its position during assembly.
Typically, corrugated pipes do not hold a very tight tolerances. If a gasket rolls or folds over as the first and second pipe sections are assembled, a fluid tight seal may not result or the corrugated pipe could be damaged. A gasket is needed that includes a support portion that prevents the gasket from rolling or folding over and maintains the gasket in tight contact with the corrugated pipe and the bell.
The present invention is directed to a reinforced annular gasket for providing a fluid tight seal between a corrugated pipe and a smooth annular section of a second member, when the corrugated pipe and the smooth annular section are in a relative surrounded and surrounding relationship. The annular gasket includes a support portion and an elastomeric gasket portion. The support portion is made from a first material having a first durometer. The support portion includes an anchor portion shaped to fit within a recess formed in a ridge of a corrugated pipe or with a groove of a corrugated pipe and a tip portion that extends radially outward from the anchor portion. The support portion is configured such that when the anchor portion is disposed in a recess in a ridge of a corrugated pipe, the tip portion extends radially outward of the ridge. The elastomeric gasket portion is made from a second material having a durometer that is less than the durometer of the support portion. The elastomeric gasket portion is disposed on the support portion. The gasket portion may be configured in any shape that creates a seal. The gasket portion is configured to make sealing contact with the ridge of the corrugated pipe and the smooth annular section when the corrugated pipe having a recess in which the gasket is received and the smooth annular section are in a relative surrounded and surrounding relationship.
In disclosed embodiments of the invention, the gasket portion includes first and second leg portions that extend laterally of first and second sides of the support portion to contact the ridge of the corrugated pipe when the gasket is installed in the recess in the ridge of the corrugated pipe. The support portion and the elastomeric gasket are coextruded or glued together. In one embodiment, the tip of the support portion includes a transition portion or neck portion having a reduced thickness. The thickness of the transition portion may be varied to increase or decrease the force required to bend or deform the transition portion. An opening may be included in the support portion to reduce the amount of material required to construct the support portion.
A fluid tight coupling that utilizes the disclosed gasket includes a corrugated pipe, an outer annular section, and an annular gasket. Corrugated pipe has an annular groove and an adjacent ridge that includes a recess. The annular section has a smooth inner surface disposed around the corrugated pipe. The annular gasket is disposed between the corrugated pipe and the annular section. The annular gasket includes a support portion made from a first material having a first durometer. The support portion includes an anchor portion disposed within the recess and a tip portion extending radially outward from the anchor portion. The tip portion extends radially outward of the ridge of the corrugated pipe. An elastomeric gasket portion made from a second material having a durometer that is less than the durometer of the support portion is disposed on the tip portion of the support portion. The elastomeric gasket portion makes sealing contact with the ridge of the corrugated pipe and the smooth annular section.
The disclosed gasket is used in a method of providing a fluid tight seal between a ridge of a corrugated pipe and a smooth inner surface of an annular section. In the method, a support portion of the gasket is inserted into a recess in a ridge of a corrugated pipe such that a tip of the support portion extends radially outward of the ridge. The ridge of the corrugated pipe is engaged with an elastomeric gasket portion of the gasket that is disposed on the support portion. The corrugated pipe is inserted into a smooth annular section having a smooth inner surface. The elastomeric gasket portion engages the ridge of the corrugated pipe and the smooth annular section to provide a fluid tight seal between the corrugated pipe and the smooth annular section.
Additional features of the invention will become apparent and a fuller understanding will be obtained from the following detailed description in connection with the accompanying drawings.